Road Traffic - Drink and Drug Driving
- Section 5 RTA 1988 - Driving or being in charge with alcohol concentration above prescribed limit
- Section 5A RTA 1988 - Driving or being in charge with concentration of specified controlled drug above specified limit
- Section 4 RTA 1988 - Driving/Attempting to drive or being in charge of a motor vehicle whilst unfit
- Section 6 RTA 1988 - Preliminary Impairment Testing
- Section 7 RTA 1988 - Request to provide a sample at police stations
- Procedure - MGDD Forms
- Procedure - Youths
- Post Driving Consumption and Back Calculations
- Challenging the evidential breath testing instrument
- Public Interest Considerations
- Disclosure of Unused Material
- Other Guidance
- Annex A - List of Drink or Drug related RTA 1988 offences
Section 5 RTA 1988 sets out this offence and provides a defence.
A person who drives or attempts to drive a motor vehicle on a road or other public place, or is in charge of a motor vehicle on a road or other public place, after consuming so much alcohol that the proportion of it in his breath, blood or urine exceeds the prescribed limit is guilty of an offence.
In relation to being in charge of a motor vehicle, a person is not guilty if he proves that the circumstances were such that there was no likelihood of his driving the vehicle whilst the proportion of alcohol in his breath, blood or urine exceeded the prescribed limit.
Section 5A RTA 1988 - Driving or being in charge with concentration of specified controlled drug above specified limit
The offence at s. 5A RTA 1988 is driving, attempting to drive or being in charge of a motor vehicle with a specified controlled drug in the blood or urine in excess of the specified limit for that drug. It is a summary only offence that came into force on 2 March 2015. It brings enforcement of drug driving into line with that of drink driving, by introducing a strict liability offence to avoid the need to prove impairment. It seeks to enable more effective law enforcement to take place, with the aim of improving road safety by deterring potential drug drivers and bringing more drug drivers to justice.
A ‘controlled drug’ is stated at s.11 RTA 1988 to have the meaning given by s.2 Misuse of Drugs Act 1971. A “controlled drug” is any substance or product for the time being specified in Part I, II or III of Schedule 2 of the Misuse of Drugs Act 1971.
Section 5A(1)(b) and (2) RTA 1988 provides for an offence of driving or being in charge of a motor vehicle with a proportion of a specified controlled drug above the specified limit.
Section 5A(3) RTA 1988 provides a defence if a specified controlled drug is prescribed or supplied in accordance with the Misuse of Drugs Act 1971 and taken in accordance with medical advice. Section 5A(4) RTA 1988 confirms that the defence is not available if medical advice about not driving for a certain period of time after taking the drug has not been followed. There is no reverse burden of proof. If a defendant raises this, the Court must assume that the defence is satisfied, unless the prosecution proves beyond reasonable doubt that it is not. The offence in S.4 RTA 1988 applies to those whose driving is impaired by specified controlled drugs taken in such circumstances. Section 4 RTA 1988 also applies to those whose driving is impaired by drugs that are not specified for the purposes of the offence.
Given that a defendant may have a medical reason for one drug but not another, it would be sensible to charge each drug offence separately; furthermore, as outlined below, given that the limits are different for each drug, there should be separate charges for each individual drug in any event.
Section 5A(6) RTA 1988 provides a defence to being in charge of a motor vehicle with a specified controlled drug in the blood or urine above the specified limit for that drug, if the defendant can show that there was no likelihood of him driving the vehicle while over the specified limit. This is similar to the defence in s. 5(2) RTA 1988.
Section 5A (2) RTA 1988 states that the specimen will be blood or urine. However, as there are no specified limits set for drugs in urine, the specimen has to be blood, and this is reflected in police procedure. If the suspect refuses, without reasonable excuse to provide a specimen of blood, the appropriate charge will be one of "Failure to provide" contrary to s.7(6) RTA 1988. A s.5A RTA 1988 offence cannot be prosecuted if the suspect has a genuine medical reason for failing to provide a specimen of blood. This would not preclude the continuation of evidence gathering for a s.4 RTA 1988, as the requirement for the presence of a drug does not need to exceed a limit and the drug can be discovered in specimens of urine. This is why police will investigate both offences where evidence of impairment is available.
Section 5A(8) RTA 1988 provides a regulation-making power to specify which controlled drugs are covered by the offence, and the specified limit in relation to each. Section 5A(2) allows different specified limits to be set for different controlled drugs. Specified limits could be set based on evidence of the road safety risk posed by driving after taking the drug, or based on an approach whereby it is not acceptable to drive after taking any appreciable amount of the drug. Section 5A(9) RTA 1988 provides that specified limits could be zero.
Regulation 2 of the Drug Driving (Specified Limits) (England and Wales) Regulations 2014 specifies the controlled drugs (within the meaning given by the Misuse of Drugs Act 1971) and the limits in blood above which it will be an offence to drive. Regulation 2 has been amended to include amphetamine.
There are currently 17 drugs listed in the related Drug Driving (Specified Limits) (England and Wales) Regulations 2014 and the Drug Driving (Specified Limits) (England and Wales) (Amendment) Regulations 2015. The levels have been set and stated in the regulations. They are based on figures from a panel of experts that has considered such factors as "accidental exposure". It is important to note that this offence is not a "zero tolerance" offence, as the limits for the illegal drugs are low but with sufficient tolerance to allow for accidental exposure.
If a blood specimen has been taken, the police will ensure that it is stored, packaged and transported in the appropriate way. This is especially important in circumstances where cannabinoids are involved, as the breakdown rate is very fast. The sample should ideally be taken within one hour, in order to be reflective of the level at the time of the offence. The specimen of blood taken will be divided and one part provided to the suspect if requested. The suspect will be given a leaflet as to what he must do with this sample to maintain its integrity. There may be challenges to the suspect’s specimen, as the concentration will reduce if it is not kept refrigerated.
The testing of both specimens must be at an accredited laboratory to ensure that the criminal justice system can be satisfied whether a person is above the specified limit. The testing is based on the same methodology as for alcohol. This is in order to allow for margins of error. The testing of specimens must be at an accredited laboratory to ensure that the criminal justice system can be satisfied whether a person is above the specified limit. Guidance issued by the Home Office and the office of the Forensic Science regulator requires analysts to allow a margin of error and the level reported will allow for that.
The Forensic Science Regulator, together with accredited Forensic Science Providers, has developed a standard approach as to how measurement uncertainty should be accounted for when reporting analyses in support of the s. 5A offence.
The Forensic Science Regulator has also published guidance on the comparison of analytical results to limits created under the provisions of s. 5A RTA 1988.
Consideration as to whether to pursue two or more charges will depend on the circumstances of the case. High readings, in relation to two or more drugs, may well justify the pursuit of two or more charges, particularly if the consequences of any driving were serious. However, there will be cases in which the Court may well look to impose a nominal penalty for a second drug, so there will be cases in which a plea to one charge will suffice.
As there are different limits for different drugs, a charge that included two or more drugs would arguably be bad for duplicity. Therefore, there should be separate charges for separate drugs.
The Sentencing Council has produced guidance, in the absence of a definitive sentencing guideline, to assist those sentencing offences under s. 5A RTA Act 1988. The guidance includes aggravating and mitigating factors, as well as factors that increase or reduce the seriousness of the offence.
If the Defendant accepts the presence of alcohol or another specified drug, this information can be placed before the Court and taken into consideration. It should be noted that if the presence of another specified drug or alcohol is likely to impact on sentence, the public interest is likely to favour an additional charge.
Under s.4(1) RTA 1988, it is an offence if a person drives or attempts to drive a motor vehicle on a road or other public place whilst unfit through drink or drugs. Similarly, s.4(2) RTA 1988 makes it an offence if the person is in charge of a motor vehicle when under the influence of drink or drugs.
It is important to note the interplay between s.4 RTA 1988 and s. 5A RTA 1998. Where the level of drugs exceeds the specified amount, the appropriate charge would be s. 5A RTA 1988. If the level of the drug does not exceed the specified limit, but where there is sufficient evidence of impairment, the charge will be contrary to s.4 RTA 1988.
The police have been advised to continue gathering evidence of impairment to support the investigation of s.4 RTA 1988. Whilst cannabis and cocaine are the most prevalent drugs amongst drug-drivers, the majority of specified drugs and other drugs and intoxicants cannot be tested for at the roadside.
Prosecutors need to be mindful of the need to distinguish between “attempting to drive” and being “in charge”. An attempt must be “more than merely preparatory” to the act of driving. In Mason v DPP  EWHC 2198 (Admin), a car owner had been robbed at knifepoint as he opened his car door. The robber drove off in the car. The car owner phoned the police who told him to come to the station and make a report. When he did, the officer smelt alcohol on his breath and arrested him for attempting to drive whilst over the limit. He later blew 68ug in breath. The Court held that opening a car door was merely preparatory to the act of driving, and not an actual attempt to drive.
A person remains in charge of their vehicle until they have transferred control to another, for example by handing over the key or have gone some distance from the car, in such circumstances that they had no intention of re-asserting control of the vehicle.
Section 6 RTA 1988 provides a power for a constable to administer preliminary tests. Section 6A RTA 1988 provides for a preliminary breath test, 6B RTA 1988 for a preliminary impairment test and 6C RTA 1988 for a preliminary drug test. Sections 6D RTA 1988 and 6E RTA 1988 make provision about powers of arrest and powers of entry respectively in connection with the administration of preliminary tests.
The preliminary tests are:
- a breath test whereby a specimen of breath is taken by means of a device approved by the Secretary of State which indicates whether the proportion of alcohol in a person’s breath or blood is likely to exceed the prescribed limit (s. 6A RTA 1988).
- an impairment test, which consists of a series of physical tasks, set by the constable. By observing the person’s ability to perform these tasks, and making such other observations of the person’s physical state as the constable thinks expedient, the constable can obtain an indication whether the person is unfit to drive and, if he is, whether his unfitness is likely to be due to drink or drugs. The Secretary of State is required to issue and to keep under review a code of practice regarding such tests (s. 6B RTA 1988)
- a drug test whereby a specimen of sweat or saliva is used, by means of a device approved by the Secretary of State, for the purpose of obtaining an indication whether a person has a drug in his body (s. 6C RTA 1988). The police will carry out a roadside test, much in the same way as the screening breath test for alcohol. Current testing devices used under s. 6C RTA 1988 only test for Delta-9-tetrahydrocannabinol (the active ingredient of cannabis) and cocaine. If the result is positive, the suspect can be arrested and taken to a police station, where an evidential specimen of blood will be required.
A person commits an offence if he fails without reasonable excuse to co-operate with a constable’s requirement for any one or more preliminary tests - s. 6(6) RTA 1988.
Preliminary tests may be administered if a constable reasonably suspects that the person:
- is driving, is attempting to drive or is in charge of a motor vehicle on a road or other public place, and has alcohol or a drug in his body or is under the influence of a drug - s.6(2) RTA 1988;
- has been driving, attempting to drive or in charge of a motor vehicle on a road or other public place while having alcohol or a drug in his body or while unfit to drive because of a drug, and still has alcohol or a drug in his body or is still under the influence of a drug s.6(3) RTA 1988;
- is or has been driving, attempting to drive or in charge of a motor vehicle on a road or other public place, and has committed a traffic offence while the vehicle was in motion s.6(4) RTA 1988;
- an accident occurs owing to the presence of a motor vehicle on a road or other public place, and a constable reasonably believes that the person was driving, attempting to drive or in charge of the vehicle at the time of the accident - s.6(5) RTA 1988.
A preliminary breath test administered in reliance on s.6(2) to (4) may be administered only at or near the place where the requirement to co-operate with the test is imposed - s. 6A(2) RTA 1988.
Preliminary tests that may be administered at or near the place where the requirement to co-operate with the test is imposed, or if the constable who imposes the requirement thinks it expedient, at a police station specified by him, are set out at s.6A(3), s.6B(4) and s.6C(2) RTA 1988. They are a:
- preliminary breath test administered in reliance on s.6(5) RTA 1988
- preliminary impairment test or a
- preliminary drug test
An obligatory requirement to provide a sample for analysis arises in circumstances set out in s. 7 RTA 1988.
If the provision of a specimen other than a specimen of breath is required, the question whether it is to be a specimen of blood or a specimen of urine and, in the case of a specimen of blood, the question who is to be asked to take it, shall be decided by the constable making the requirement. However, there is no requirement to provide such a specimen if:
- the medical practitioner who is asked to take the specimen is of the opinion that, for medical reasons, it cannot or should not be taken; or
- the registered health care professional who is asked to take it is of that opinion and there is no contrary opinion from a medical practitioner.
A specimen of urine shall be provided within one hour of the requirement for its provision being made and after the provision of a previous specimen of urine.
A constable must provide a warning on requiring a specimen that a failure to provide it may render him liable to prosecution and may arrest a person without warrant if the person fails to provide a specimen. Failure, without reasonable excuse, to provide a specimen when required is an offence – s. 7(6) RTA 1988.
If "reasonable excuse" is raised as a defence based on medical evidence, the prosecutor should require the defence to provide that evidence before the hearing, or seek an adjournment for that purpose. The matter can then be investigated and, if necessary, expert medical evidence obtained which addresses the specific issues raised by the defence. In DPP v Crofton (1994) RTR 265 it was held that the court should consider the following matters in such circumstances:
- medical evidence of physical or mental inability to provide the specimen;
- the causative link between the physical or mental condition and the failure to provide the specimen.
Once such a defence is raised, the onus is upon the prosecution to negate it.
A specimen may be required in the course of an investigation into whether a person has committed an offence under:
- s.3A RTA 1988 - Causing death by careless driving when under influence of drink or drugs;
- s.4 RTA 1988 - Driving, or being in charge, when under influence of drink or drugs, or
- s.5 RTA 1988 - Driving or being in charge of a motor vehicle with alcohol concentration above prescribed limit;
- s.5A RTA 1988 - Driving or being in charge of a motor vehicle with concentration of specified controlled drug above specified limit.
A constable may make a requirement under s.7 RTA 1988 to provide specimens of breath only if the requirement:
- is made at a police station or a hospital,
- where s.6(5) RTA 1988 applies (an accident occurs owing to the presence of a motor vehicle on a road or other public place, and a constable reasonably believes that the person was driving, attempting to drive or in charge of the vehicle at the time of the accident), or
- the constable is in uniform.
Section 8 RTA 1988 provides that of any two specimens of breath provided by any person in pursuance of s.7 RTA 1988 that with the lower proportion of alcohol in the breath is to be used and the other disregarded.
A requirement to provide a specimen of blood or urine can only be made at a police station or at a hospital - s.7(3) RTA 1988. It cannot be made at a police station unless:
- the constable making the requirement has reasonable cause to believe that for medical reasons a specimen of breath cannot be provided or should not be required - s.7(3)(a) RTA 1988, or
- specimens of breath have not been provided elsewhere and at the time the requirement is made a device or a reliable device of the type mentioned in s.7(1)(a) RTA 1988 is not available at the police station or it is then for any other reason not practicable to use such a device there - s.7(3)(b) RTA 1988, or
- a device of the type mentioned in s.7(1)(a) RTA 1988 has been used at the police station or elsewhere but the constable who required the specimens of breath has reasonable cause to believe that the device has not produced a reliable indication of the proportion of alcohol in the breath of the person concerned - s.7(3)(bb) RTA 1988, or
- as a result of the administration of a preliminary drug test, the constable making the requirement has reasonable cause to believe that the person required to provide a specimen of blood or urine has a drug in his body - s.7(3)(bc) RTA 1988, or
- the suspected offence is one under s. 3A RTA 1988, s. 4 RTA 1988 or s. 5A RTA 1988 and the constable making the requirement has been advised by a medical practitioner or a registered health care professional that the condition of the person required to provide the specimen might be due to some drug - s.7(3)(c) RTA 1988.
Where a requirement to provide blood or urine applies the requirement may then be made notwithstanding that the person required to provide the specimen has already provided or been required to provide two specimens of breath.
Under s.7(3)(c) RTA 1988 a constable may require a driver to provide a laboratory specimen when a medical practitioner has advised him that the condition of the driver might be due to a drug. The purpose of this provision is neither to prove that the driver is, or that the doctor believes him to be, under the influence of drugs - but simply to advise that the driver's condition might be due to some drug. The doctor is not prohibited by the words of that statute from taking into account any fact or matter which he feels to be relevant. He is not restricted to considering the condition of the driver at the time of his examination. Officers are now frequently testing for driver impairment due to drugs at the roadside. The tests are primarily based on the physical response of the driver to certain tasks. The doctor may consider the results of such tests when he advises a constable under s.7(3)(c) RTA 1988.
A constable may ask a medical or health care practitioner to take a specimen of blood irrespective of whether that person consents if:
- the constable would have been entitled under section 7 to require the provision of a specimen of blood for a laboratory test,
- it appears that the person has been involved in an accident;
- it appears that the person is or may be incapable of giving a valid consent for medical reasons.
Such a request is not to be made to a medical or health care practitioner with responsibility for the clinical care of the person concerned. The blood specimen can be taken irrespective of whether that person consents. However, that specimen is not to be subjected to a laboratory test unless the person from whom it was taken
- has been informed that it was taken
- has been required by a constable to give his permission for a laboratory test of the specimen, and
- has given his permission.
On requiring a person to give his permission, the constable must warn that person that a failure to give permission may render him liable to prosecution. A person who, without reasonable excuse, fails to give his permission for a laboratory test of a specimen of blood taken from him is guilty of an offence.
Section 9 RTA 1988 provides protection for hospital patients. A patient is not to be required to co-operate with a preliminary test, to provide a specimen under s.7 RTA or a specimen of blood under s.7A RTA 1988 unless the medical practitioner in immediate charge of his case has been notified of the proposal to make the requirement; and does not object.
The medical practitioner may object on grounds that the warning about the consequences of not providing or the taking of the specimen would be prejudicial.
The Manual of Guidance drink and drug driving (MGDD) prescribes a set of forms that is used by forces in England and Wales when dealing with drink and drugs driving offences. Prosecutors should note the contents of the forms and the procedures that they prescribe.
The procedure for requiring a specimen
- of breath is set out in MGDD Form A
- of blood or urine is set out in MGDD Form B
- at hospital is set out in MGDD Form C
Other forms that set out relevant procedures are
MGDD Form D - Alcohol technical defence and back calculation
MGDD Form E - Drug drive laboratory submissions
MGDD Form F - Roadside Impairment testing
In the event of a not guilty plea to a summary drink/drive offence, you should try to obtain a formal admission under Section 10 of the Criminal Justice Act 1967 as to the contents of the Form. Such an admission must include the name of the defendant, the date and place of the offence and the results of the breath test or of the laboratory test. If such an admission cannot be secured then the officers conducting or witnessing the sampling procedure will normally have to be called to give evidence in person.
The Form MG/DD contains assertions of fact; it is a document made out of court and is inadmissible under the hearsay rule. Section 9 Criminal Justice Act 1967 only permits that the evidence contained in a witness statement is admissible were the maker of it in the witness box. If the officer who filled out the Form were in the witness box, he could not produce the Form in chief as an exhibit, though he could refer to it as a memory-refreshing document. The production in evidence of that Form attached to a short s.9 CJA statement will not render the content admissible.
The only way in which the information contained on a Form MG DD can be produced in documentary form as admissible evidence is if that information is extracted from the form and incorporated into a s.9 CJA statement made by the officer. This course must be followed in the event of a prosecution under s.3A of causing death by careless driving when under the influence of drink or drugs.
MGDD Form A provides guidance on taking a sample in cases involving a person aged 17 years or under. The young person may consent to the provision of breath, blood or urine specimens without the need for parental or other approval. The officer must be satisfied, as they would with any consent, that the young person has the necessary mental capacity. The prosecution need not be delayed until an appropriate adult attends since the procedure does not constitute an interview for the purposes of PACE.
The youth must have sufficient capacity to understand what he/she is being asked to consent to and the consequence of refusing to provide the specimen (namely, that a failure or refusal, to provide it, without reasonable excuse, may render him/her liable to prosecution for an offence of failing to provide).
A driver may claim that the proportion of alcohol in a breath or laboratory specimen is above the legal limit because he consumed alcohol after he ceased to drive. The driver will need to rebut the presumption contained in s.15(2) RTOA 1988 that the proportion of alcohol in his breath, blood or urine at the time of the alleged offence was not less than in the specimen. That presumption can be rebutted if the driver proves the matters set out at s. 15(3) RTOA 1988 on a balance of probabilities. This usually requires expert scientific evidence to establish that the alleged post driving consumption of alcohol accounts for the excess found in the sample.
It was held in Dawson v Lunn RTR 234 that Pugsley v Hunter  RTR 284, the leading authority on "laced drinks", is equally applicable to this defence. The defence must call medical or scientific evidence on the point unless it is obvious to a layperson that the post offence consumption explained the excess. Experience has shown that this is frequently argued in cases where the defendant claims to have consumed no alcohol prior to driving. Even here, it will not be "obvious" where the quantity of alcohol subsequently consumed is not consistent with the measured breath, blood or urine sample.
Conversely, a driver may provide a specimen some hours after the time of the alleged offence that is below the legal limit. The Forensic Service Provider may advise that back calculations based upon rates at which the human body eliminates alcohol could establish that the driver was in excess of the legal limit when the offence occurred. The prosecution are entitled to rely upon such back calculations for the purposes of proving an offence under s.5 RTA 1988 - see Gumbley v Cunningham (1989) 1 All ER 5 - but only if that evidence is easily understood and clearly persuasive of the presence of excess alcohol at the time of the alleged offence.
Expert evidence from the Forensic Service Provider will include evidence of mathematical calculations based upon the elimination of alcohol within the driver's body. Ideally, the evidence provided by the Forensic Service Provider should relate as closely as possible to the physical characteristics of the driver and his consumption of both food and drink over the relevant period.
The officer will normally record information required by the expert on the Form MG/DD/D at the police station. However if the defence is not raised until a later time the FSP should be provided with as much information as can be obtained from the case papers and the officer in the case. The following information is relevant, where available:
- the weight, height, build, age and sex of the driver;
- details of any food consumed from six hours before the offence and the provision of a breath or laboratory specimen;
- any known medical condition;
- details of any medication taken regularly, or within 4 hours prior to drinking;
- the type and quantity of alcohol consumed before the offence and, if possible, the times at which individual units of alcohol were consumed;
- the same information concerning any alcohol allegedly consumed after the offence but before the provision of a breath or laboratory specimen.
The first generations of Evidential Breath Testing Instruments were replaced in 1999. All forces are now equipped with the Intoximeter EC/IR, the Camic Datamaster or the Lion Intoxylizer 6000UK. They detect and record a wider range of information when analysing breath samples.
These three makes of instrument are a type approved by the Secretary of State for the purposes of the Road Traffic Act. Any challenge of that type approval must be made by way of an application for Judicial Review, not in the course of a summary trial relating to the performance of a particular instrument: (see DPP v Brown and DPP v Teixeira  EWHC Admin 932, 166 JP 1).
There is a statutory presumption at s.15(2) RTOA 1988 that at the time that the defendant was driving the proportion of alcohol in their breath, blood or urine was at least what was found in the specimen. However, that presumption may be challenged by evidence relevant to the circumstances of that particular case. In order to convict in the face of such evidence the court must remain satisfied that the instrument provided a reading upon which they can rely. See Cracknell v Willis(1988) 1 AC 450 at 467, and DPP v Brown; DPP & v Teixeira, supra.
Prosecutors should be robust in challenging speculative defence applications for disclosure of material such as calibration service sheets or engineers’ reports, for example relating to the history of the machine which produced the reading relied on.
The disclosure duties under the Criminal Procedure and Investigation Act 1996 (‘CPIA’) only apply to material which is in the possession of the prosecutor or which the prosecutor has inspected or which the prosecutor must, if they ask for the material, be given a copy or must be allowed to inspect (CPIA sections 3 and 8). The manufacturers of a breath testing device are third parties and any records they hold relating to the machine are not ‘prosecution material’ within the meaning of the CPIA. (DPP v Wood and McGillicuddy  EWHC 32 (Admin)).
Records held in the custody suite are in the possession of police (but not the prosecutor). However, these will only meet the definition of ‘prosecution material’ if they are relevant and it would constitute a ‘reasonable line of enquiry’ for the prosecutor to ask the police to provide them (section 8(4) CPIA). If there is no reason to believe that they contain anything relevant which would meet the criteria for disclosure under the CPIA then obtaining them will not be a reasonable line of enquiry. Therefore, defence applications for disclosure of this sort of material must identify a proper evidential basis for concluding that the material sought might reasonably be expected to meet the criteria for disclosure. (See:DPP v Manchester and Salford Magistrates’ Court  EWCH 3719 (Admin)), followed in DPP v Walsall Magistrates' Court & Anor  EWHC 3317 (Admin) (05 December 2019).
Evidential Breath Testing Instruments are computers. Following the repeal of section 69 PACE 1984, the law has reverted to the common law position which presumes that any mechanical or other device is working properly unless the contrary is proved (affirmed in Clarke v CPS  EWHC 366 (Admin)). Consequently the record produced by a computer is admissible as real evidence as it is presumed that the record is accurate. That presumption can be rebutted if evidence to the contrary is adduced. In that event, it will be for the party seeking to produce the computer record in evidence to satisfy the court that the computer was working properly at the material time.
There is a very clear public interest in prosecuting drink or drug driving offences, due to the danger posed to others by such behaviour. Where an individual has driven a motor vehicle and the evidence is sufficient to support a charge under s.4, 5, 5A or 7(6) RTA 1988, a prosecution will almost invariably follow.
Offences contrary to sections 6(4) and 7(6) RTA 1988 may be committed whether the defendant has been driving, attempting to drive or in charge of a vehicle. Where you are satisfied that the defendant has done none of those acts there is a greater degree of discretion as to whether proceedings are appropriate. However, particularly where an offence under s.7(6) RTA 1988 is involved, a prosecution will normally be in the public interest.
When considering a request from the police for back calculations or reviewing a case based upon such evidence, you should consider whether such a prosecution would be in the public interest. Factors to consider in the context of such a case in favour of prosecution might include:
- where a considerable lapse of time occurred between the incident of driving and the driver's arrest because of the driver's own culpable actions by, for example, absconding from the scene of an accident;
- where there are clear grounds for believing the driver to be a danger to other road users, such as the existence of previous drink/drive convictions;
- where there are other aggravating features, such as the fact that the driver was disqualified from driving or serious injury was caused to another person.
When a death occurs because of careless driving when under the influence of drink or drugs, you should refer to Road Traffic - Charging, elsewhere in the Legal Guidance.
In most cases of drink/driving, there will be scientific and/or medical evidence to show that the driver has exceeded the prescribed limit. In such cases, a charge under s.5 will be proper. Although the prescribed breath alcohol limit is 35 micrograms, a driver will not be prosecuted under s.5 with a breath alcohol level of less than 40 micrograms. This is in accordance with the guidelines contained in Home Office Circular 46/1983. That level will usually be taken as that recorded by an evidential breath testing machine or by analysis of a blood/urine sample. However, it may be the level as determined by back calculations.
If there is clear evidence of impairment over and above the evidence of the breath analysis, you should consider charging a s.4 offence in preference to that under s.5.
If evidence supports an allegation of unfitness, joint proceedings for both section 4 and 5 offences are normally unnecessary. But you should consider charging both when:
- evidence indicates impairment as a result of both drugs and excess consumption of alcohol;
- there is a possible defence to the s.5 offence because the sample taken by the police is likely to be ruled inadmissible.
Where there is evidence to support unfitness for a charge under s.4, and also evidence to support an allegation of failing to provide a specimen for a laboratory test under s.7(6), you may charge both offences. That may be particularly appropriate if there is a possible defence to the charge of failing to provide a specimen.
A charge of failing to provide a specimen of breath for screening under s.6(4) should be preferred when supported by the evidence. In the event of a guilty plea being tendered to a related offence under sections 4, 5 or 7(6) it will not normally be in the public interest to proceed with the charge under s.6(4).
There is no need to state in a charge under s.7(6) the offence which is suspected and being investigated by a police officer: see DPP v Butterworth (1994) 3 WLR 538. It is the fact that an investigation is in process that gives rise to the requirement to provide a specimen for analysis. The nature of the offence under investigation is relevant only to penalty; it may be necessary to have a "Newton" hearing to determine if the defendant had driven, or was in charge of, a vehicle on a road.
Standard records, such as the maintenance log for each instrument, does not form part of the investigation into an offence, will not form part of the standard unused material of an investigation, and should not be routinely disclosed to the defence.
The defence may request copies of technical documents relating to the specification, construction and performance of the instruments. Disclosure to the defence of such unused material is governed by the usual CPIA rules on defence material - see also DPP v McKeown, DPP v Jones (1997) RTR 162. You should bear in mind that material in this category might be commercially confidential.
If there is any reason to believe that an instrument whose readings are relied upon in evidence was not working correctly that information, which will undermine the prosecution case, must be disclosed to the defence.
Prosecutors should also note the (restricted) operational guidance on specialist defences in Annex B of this document on:
- Defence challenges on drink/drug drive offences and how to address them
- Specialist challenges on drink/drug drive offences (which covers some additional points)
- Common disclosure requests and how to approach them
- Schedule of helpful authorities on defence challenges.
Drink or Drug related RTA Offence
Cause death by driving without due care / consideration while unfit through drugs
Cause death by due care and fail to provide specimen
Cause death by driving without due care and attention / reasonable consideration while unfit through drink
Cause death by due care while over prescribed limit
Cause death by driving without due care / consideration while over specified limit - specified controlled drug
Fail to give permission for a laboratory test on a blood specimen having caused a death
Drive whilst unfit through drink
Drive a vehicle whilst unfit through drugs
Attempt to drive vehicle whilst unfit through drink
Attempt to drive vehicle whilst unfit through drugs
In charge of vehicle whilst unfit through drugs
In charge of vehicle whilst unfit through drink
Drive motor vehicle when alcohol level above limit
Attempt to drive motor vehicle - alcohol level above limit
In charge of motor vehicle - alcohol level above limit
Drive motor vehicle with a proportion of a specified controlled drug above the specified limit
S. 5A(1)(a) and (2)
In charge of a motor vehicle with proportion of specified controlled drug above specified limit
S. 5A(1)(b) and (2)
Fail to co-operate with a preliminary test - motor vehicle offence
Fail to provide specimen for analysis - vehicle driver
Fail to provide specimen - person in charge of vehicle
Attempt to drive a motor vehicle with a proportion of a specified controlled drug above the specified limit
S. 5A(1)(a) and (2)
Aid abet the driving of a motor vehicle with a proportion of a specified controlled drug above the specified limit
Drive / attempt to drive vehicle and fail to allow blood specimen taken while incapable of giving consent to be analysed
In charge of a vehicle and fail to allow specimen of blood taken while incapable of giving consent to be analysed
Riding pedal cycle under the influence of drink or drugs